You may want to consider that 5GHz barley penetrates walls.
It is very short range - very high speed.
The 2.4 GHz penetrates walls etc much better however is lower throughput.
After much experimenting I decided its best left to the devices to decide which network is the fastest at its location (too much hassle otherwise).
I have setup a roaming network with identical SSID and pw for 2.4+5GHz.